Figure 4. Fluctuations in serum biochemical markers of bone turnover over the estrous cycle and their correlations with serum estradiol or progesterone. (A) TRAP activity. (C) Pyridinoline. (E) Osteocalcin. (G) Calcium. (H) Phosphorus. E, estrus; M, metestrus; D, di-estrus; P, pro-estrus. Each column represents the mean ± SEM of 6 to 8 samples. *p < 0.05, **p < 0.01, by the Tukey-Kramer test. (B) Correlation between TRAP activity and estradiol (r = -0.42, p < 0.05). (D) Correlation between pyridinoline and estradiol (r = -0.58, p < 0.001). (F) Correlation between osteocalcin and progesterone (r = 0.47, p < 0.01).
